Direct drives, available from CNC Design , are suitable when maximum dynamics and accuracy are required. Direct drives are integrated in the machine and transmission elements, such as gears, lead screws or toothed belts, can be omitted. This arrangement ensures a high degree of control stiffness, better dynamic response and high precision in less space.
The function, performance and accuracy of the electrical components used are the factors for productivity and the quality of the output from machines and systems as well as the mechanical execution of the task. The drive concept also influences the life cycle costs of a machine.
Torque motors are direct drives for rotary axes, which require precision and force at low speed. Torque motors have a high degree of precision and dynamic performance as well as low wear. As their maintenance and space requirements are minimal, they are used as an alternative to geared motors. CNC Design offer 1FW3 and 1FW6 torque motors.
The 1FW3 and 1FW6 torque motors are synchronous motors, which operate similar to rotary synchronous servo motors. The rotor is equipped with permanent magnets and the stator contains motor windings. The multi-pole design of the windings endows the motor with maximum torques at low speed. The 1FW3 and 1FW6 torque motors are suitable for precise operation of rotary axes when high torque is required.
As large number of poles, mechanical transmission elements and the associated backlash or frictional losses are dispensed with, 1FW3 and 1FW6 torque motors have the following advantages:
- High torque
- High rotational accuracy
- High acceleration capability
- Space-saving design
- Low maintenance
- High efficiency
The 1FW3 series of torque motors are motors in the torque range between 100Nm and 7000Nm and are compact torque motors which, need to be flange-mounted to the machine and the rotor connected to the machine shaft. The 1FW3 series of torque motors are used in production machines for:
- Main drives for extruders
- Worms for injection moulding machines
- Roller drives for paper machines
- Winders for packaging and paper machines
- Handling and assembly systems
The 1FW3 series of torque motors are built-in torque motors. The high ratio between the peak and continuous torque makes these motors suitable for positioning and interpolating motion. The stator and rotor are supplied as individual components and are integrated directly in the machine. Its geometry makes it suitable with all the bearings which are used. Integrating torque motors into a machine is a high-precision operation. The 1FW6 series of built-in torque motors are used in machine tools for:
- Rotary tables
- Swivel axes
- Fork heads
- Rotary indexing tables
- Dynamic tool magazines
- Turning spindles
The 1FW3 and 1FW6 torque motors have a large hollow bore, with which the motor can be pushed onto the machine shaft. Media or mechanical components can be guided through the cavity in the rotor.
For speed and position control, the 1FW3 motor has a built-in shaft encoder. This must be fitted to the machine for 1FW6 motors. The 1FW3 and 1FW6 torque motors are water-cooled as standard in order to achieve a high power density. The cooling method reduces the amount of heat transferred into the machine.
Users who produce their own motor spindles can obtain suitable built-in motors from CNC Design. These motors are characterised by their compact design, ruggedness, high precision and accuracy. CNC Design offer three different types of built-in motors for motor spindles:
- The 1PH2 built-in asynchronous motor is employed as a compact, standard built-in motor for turning and grinding spindles with maximum speeds of up to 10,000 rpm.
- The ‘High Torque’ version of the 1FE1 motor is characterised by high torques and achieves peak speeds of 20,000 rpm.
- The ‘High Speed’ version of the 1FE1 motor is characterised by fast acceleration rates and achieves maximum speeds of 40,000 rpm.
The 1PH2 built-in motor is an asynchronous motor. The rotor, which is the squirrel-cage type, and the stator, which is equipped with windings, are delivered as components and are combined to form a motor spindle that is then installed in the machine. The same applies to the 1FE1 motors. These are synchronous motors with a rotor that is equipped with permanent magnets.
These motors use water cooling to dissipate the heat. The position is sensed by external encoders. As mechanical power transmission elements (belts, gears) and the backlash are dispensed with, built-in motors have the following advantages:
- Better surface finish
- High acceleration capability
- High rigidity as a result of the compact design
- Wear-free
- High efficiency
These built-in motors are suitable for use in motor spindles for machine tools. The 1PH2 motors are used for grinding or turning spindles and the 1FE1 motors are suitable for turning, grinding and milling spindles. Due to the high level of integration of direct drives in the machine, attention must be paid to storage and cooling.